# HG changeset patch
# User Christian Urban <urbanc@in.tum.de>
# Date 1480612092 0
# Node ID ea0d0a862a9c6466fa4f8a88334e263eae9c1820
# Parent  2d57b0d43a0fad2a13a73f494db8bde47b904cf8# Parent  3cbe3d90b77f2bd00c154d1afbab37d66a524636
merged

diff -r 2d57b0d43a0f -r ea0d0a862a9c progs/lecture2.scala
--- a/progs/lecture2.scala	Thu Dec 01 17:08:02 2016 +0000
+++ b/progs/lecture2.scala	Thu Dec 01 17:08:12 2016 +0000
@@ -180,9 +180,6 @@
 
 
 
-
-
-
 def my_flatten(lst: List[Option[Int]]): List[Int] = lst match {
   case Nil => Nil
   case None::xs => my_flatten(xs)
@@ -200,6 +197,20 @@
 
 get_me_a_string(0)
 
+// you can also have cases combined
+def season(month: String) = month match {
+  case "March" | "April" | "May" => "It's spring"
+  case "June" | "July" | "August" => "It's summer"
+  case "September" | "October" | "November" => "It's autumn"
+  case "December" | "January" | "February" => "It's winter"
+}
+ 
+println(season("November"))
+
+// What happens if no case matches?
+
+println(season("foobar"))
+
 // User-defined Datatypes
 //========================
 
diff -r 2d57b0d43a0f -r ea0d0a862a9c progs/lecture3.scala
--- a/progs/lecture3.scala	Thu Dec 01 17:08:02 2016 +0000
+++ b/progs/lecture3.scala	Thu Dec 01 17:08:12 2016 +0000
@@ -116,9 +116,17 @@
 searchT(111, junk_coins, start_acc)
 searchT(111111, junk_coins, start_acc)
 
-// moral: whenever a recursive function is resource-critical
-// (i.e. works on large recursion depth), then you need to
-// write it in tail-recursive fashion
+// Moral: Whenever a recursive function is resource-critical
+// (i.e. works with large recursion depths), then you need to
+// write it in tail-recursive fashion.
+// 
+// Unfortuantely, the Scala is because of current limitations in 
+// the JVM not as clever as other functional languages. It can 
+// only optimise "self-tail calls". This excludes the cases of 
+// multiple functions making tail calls to each other. Well,
+// nothing is perfect. 
+
+
 
 
 // Polymorphic Types